The present invention concerns a brake, substantially for a light-constructed transport carriage, said carriage comprising a frame part, wheels, and a draw means, said draw means being turnably connected to the frame in such manner that it can be lifted into upright position to produce a braking effect.
Transport carriages like this are particularly used at airports for transporting air cargo containers. They are often towed in a string with the aid of a truck or equivalent. Because of the safety regulations in force on airports, the carriages must have a brake which arrests at least one wheel, whereby the carriage when it is loose cannot be set in motion inadvertently by the wind or by an airplane's slipstream. The brake may also be called a parking brake because it is primarily used to hold the carriage stationary.
Many different kinds of brake mechanism have been used in transport carriages heretofore. One such is a drum brake resembling a car brake and which is arrested by lifting up over a cable the draw means or a rope connected to the drum brake. A drum brake may be provided on one or several wheels. Also in use is a brake rod operated over a cable or a chain and which engages with the outer surface of a wheel or wheels when the draw means is lifted up. A brake shoe may naturally also be used instead of the brake rod.
These brake mechanisms of prior art are however embarrassed by several drawbacks which render their use unreliable and awkward. The drawback of a drum brake is its seizing, in which case the wheel cannot rotate. On the other hand, the holding capacity of the drum may diminish owing to wear, rusting or another cause. A brake shoe, again, loses its hold, or requires adjustment, when the wheel and/or the shoe suffers wear.